This invention relates to a motor/generator provided with a plurality of rotors.
Tokkai-Hei-11-275826 published by the Japanese Patent Office in 1999 and U.S. Pat. No. 6,049,152 disclose a motor/generator which controls a plurality of rotors independently with a single inverter. The inverter supplies a composite current comprising control currents corresponding to the respective rotational phases of each rotor to a single stator or a plurality of stators.
It is an object of this invention to reduce switching loss resulting from the generation of a composite current by an inverter in the above type of motor/generator.
In order to achieve the above object, this invention provides a motor/generator device comprising a stator, a first rotor associated with the stator, a second rotor associated with the stator, an inverter connected to the stator, and a microprocessor programmed to control the inverter to cause a composite electrical current of a first electrical current associated with a rotation of the first rotor and a second electrical current associated with a rotation of the second rotor, to flow between the inverter and the stator. The composite electrical current has a composite waveform combining a waveform of the first electrical current and a waveform of the second electrical current while an average value of the composite electrical current is smaller than the sum of an average value of the first electrical current and an average value of the second electrical current.
The details as well as other features and advantages of this invention are set forth in the remainder of the specification and are shown in the accompanying drawings.